Traveling grate stoker



Oct. 28, 1952 D. J. MossHART TRAVELING CRATE STOKER Filed Nov. l2, 19492 SHEETS-SHEET l INVENTR A am a unnnfmwur Nw O wlTNEssEs; p60. @w Cia;

. DONALD J. MOSSHART WTSM ATTORNEY Oct. 28, 1952 D 1 MOSSHART 2,615,406

" TRAVELING GRATE STOKER Filed NOV. l2, 1949 2 SHEETS-SHEET 2 WITNESSES:INVENTOR DONALD `LMossHART nd@ My I L', BY u Hij? A l l mi' -M M iATTORNEY Patented Oct. 28, 1952 f 1g-.:

, Westinghouse Electric Corporation, EastPittsv K burgh, Pa., acorpination4 of Pennsylvania., v,

This invention relates4 toy stokers, more particularly to 'those of thetraveling grate type, and has for' an object to provide improvedapparatus of this character.

Another object vof the.: invention is tor provide an improved scraperfor removing ash from the discharge end of a traveling lgrate anddirecting ittoanashpit.- l f Yet another object of the invention is'toprovide a traveling grate stokerv having a plenum chamber beneath theentire grate, together with an ash pit external to the plenum chamber.

A further object of the invention is to provide a reciprocating scraperfor removing ash and refuse from the discharge end of the travelinggrate of a stoker, said scraper being so arranged that it effectivelyencloses the ash discharge end of the grate and prevents ow of air fromthe plenum chamber to the ash pit.

These and other objects are effected by my invention as will be apparentfrom the following description and claim taken in connection with theaccompanying drawings, forming a part of this application, in which:

Fig. 1 is a longitudinal sectional view through tail, particularly toFig. l thereof, the reference character I0 indicates, in its entirety, atraveling grate to which fuel is fed by mechanism of the spreader type,indicated in its entirety by the reference character il. The -fuelfeeding mechanism Il comprises a hopper l2 from which fuel discharges bygravity to a ram box i3 in which reciprocate one or more rams I4 whichpush fuel rearwardly (from left to right as viewed in Fig. 1) over aspill plate IG from gravitational discharge over the rear edge I1thereof to a rotary impeller I8 disposed therebelow. The blades I9 ofthe impeller project the fuel rearwardly through the fuel feed opening2| in the front wall 22 of the furnace 23, and through the atmosphere ofthe combustion chamber 24 thereof above the fuelsupporting surface 25 ofthe traveling grate I0, the ne fuel particles burning in suspension .andthe heavier particles and pieces falling onto the rear portion of thegrate whereon they are gradually advanced by forward travel of the upperrun 21 of the grate l0 for discharge as ash and refuse to the ash pit2S.

The. trave-ling grate Il):` comprises. the-'susual structural frameworkvincluding longitudinallyextending members 33 and transverse=members34andv (Fig.Y 1). A lpair ofy transverse spaced lparallel shafts31'and'are journaled in. bearings (not shown) kmountedin the members33. and

carry.- sprockets 39 ron which-'2 aregmounted, the

.grate bars.42 attached vthereto fbyfv links'43- permitting limitedpivotal movement of the bars lbetween the two Vpositions shown in Fig. 1at the top run 21 and the bottom run 44. Each chain 4| is supportedbetween its sprockets 39 by a series of rollers 46 mounted betweenadjacent pairs of structural members 33. Mechanism (not shown) functionsto drive the left-hand sprocket counterclockwise as viewed in Fig. 1 formotivating the grate to effect travel of the upper run 21 from right toleft.

A plenum chamber 50 is provided beneath the traveling grate and isdefined by front and rear end walls 5| and 52, respectively, and sideWalls 53. A sealing structure 54-56 extends forwardly from the upperedge of the plenum chamber rear wall 52 in overlying relation to therear sprocket 39 and the grate thereon.

At the front or discharge end of the grate there isl a sealing andscraping member 51, here-l inafter referred'to as a scraper. The scraperincludes a horizontal ash and refuse-receiving portion 58 adapted torest upon the upper surfaces of the grate bars 42, and an ash andrefusedischarging portion 59 curved or inclined downwardly and away fromthe receiving portion 58, the two portions preferably being integral(Figs. 1 and 2).

As best shown in Fig. 2, the scraper 51 has a plurality of pairs of lugs6l, to which links 62 are connected by suitable means, such as the pins"53. The opposite ends of the links 62 are pivotally connected, by pins64, to bifurcated arms 66 iixedly secured to a transversely-extendingrocker shaft 61. It will be apparent from consideration of Fig. l, thatoscillation of the rocker shaft 61 will eiect reciprocation of thescraper 51 in directions substantially parallel to y the direction oftravel of the grate upper run`21,

and that during its rearward travel it Will move beneath the dischargingash and refuse at the forward or left-hand end of the grate, as viewedin Fig. l. To aid penetration of the receiving portion 58 of the scraperbeneath the oppositelymoving bed of ash and refuse, the rearward edge ofthe scraper is tapered or chamfered. as at 68 (Fig. 1).

The discharging portion 59 of the scraper overy lies a horizontalsurface 69 at the upper edge of the plenum chamber end wall 5l and ismaintained in sealing relation thereto by one or more plates 1l movablevertically in slots 'l2 provided in the seal assembly 'I3 secured to thelower end of the scraper discharge portion 59 (Fig. 3). Thus, in eiect,the scraper 51 functions as a continuation of the plenum chamber endwall 5l,

to limit upward discharge of air from the plenum chamber to that portionof the grate which sup-` l ports the burning fuel bed.

art that it is not so limited, butl is susceptible of various changesand modications without departing from the spirit thereof.

What I claim is:

In a Stoker, a traveling grate comprising a pair ,of' transverse spaced'parallel shafts, sprockets on said shafts,.endless chains on saidsprockets,

transversely-extending grate bars secured to said chains with the upperrun thereof providing y'a 'fuel-supporting' grate surface, andstructural members supporting'the upper run of said grate bars formaintaining said fuel-supporting surface at; wall structure dening aplenum chamber beneath the entire traveling grate, the wall 4 of saidplenum chamber at the discharge end of the traveling grate separatingthe plenum chamber from an ash pit and terminating at its upper edge ina substantially horizontal surface; and a reciprocal scraper lassociatedwith the discharge end of the .traveling grate and comprising an ash andrefuse-receiving portion resting on the discharge 'end Aof the gratefuelsurface of said plenum chamber end wall upper n l edge and havingsliding movement on said sur- While I 'have shown my invention in butoneform, it will be obvious to those skilled in they face duringreciprocation of the scraper.

DONALD J. MOSSHART.

REFERENCES CITED The following references are of record in the rile ofthis patent:

UNITED STATES PATENTS Name s Date-l 2,511,935 Midgette et al June 20,1950 FOREIGN PATENTS v Number Country Date 13,215 Great Britain Y 1 v1906 199,295 Germany f June 11, 1908 178,021 Great Britain Apr. 13, 1922

